APC Electric Speed 400 Series props offer high efficiency and great value for your electric powered models. These props are designed for high speed operation on Pylon Racers, Hot-liners, Flying wings and other similar applications. The center hole of the prop is designed to accept a reducing bushing to fit your propeller shaft. Included with the prop are 2 bushings to fit 5mm and 3/16 inch prop shafts.
According to the widely accepted Maximum RPM formula of 190,000/D for APC E-Series props, the 4.1x4.1 prop should not be used over 46,341 RPM.